Common Name Garden mum, garden chrysanthemum, hardy chrysanthemum, hardy mum, mum Plant Type Herbaceous perennial Mature Size 4 to 36 inches tall and 12 to 36 inches wide (size varies depending on the variety) Sun Exposure Full sun Soil Type Rich, humusy, moist, well-draining Soil pH 6.5 to 6.7 Bloom Time Late summer and fall Flower Color Gold, white, off-white, yellow, bronze (rust), red, burgundy, pink, lavender, and purple Hardiness Zones 3 to 9 Native Area Asia, Europe Toxicity Toxic to dogs, cats, horses.From late spring to mid-summer, pinch back the tips and flower buds on all shoots to make the plant bushier and prepare it for a dramatic fall show.After the blooms fade, cut the plants down to about 6 inches, and cover them with straw or another dry mulch to protect the roots over winter.That's especially true when you pair them with other late-season bloomers, such as sedum, goldenrod, Russian sage, asters, and gaillardia.Furthermore, because mums flower so late in the season, they are nondescript, though not unattractive, in the garden until blooming time.As the spring flowers die back, the mums will fill in and hide their unattractive fading foliage.Mums set buds in response to day length, so avoid confusing them by planting where they might be exposed to bright nighttime light from a patio or window or even a streetlight.And regions with hard winter freezing can see the plants succumb to cold unless they are covered with deep mulch.For fall-planted mums to have a better chance of survival in cold areas, you need to give the roots and crown of the plant extra protection.That way any new growth forced by the nutrients will not be in danger of damage from icy weather.The original species are often unclear, but horticulturalists generally categorize garden mums by flower shape:.Familiar globular shape Regular incurve: Petals curve up and in, forming a sphere.Looks like its cousin, the daisy Spider: Long, curled petals droop down and give a spider-like look.To obtain the exceptional varieties or exhibition mums, you will need to start from seed or order from a nursery or specialty mail-order company.‘Clara Curtis’ is a long-lasting variety that blooms relatively early in the season with single or semi-double pink flowers.‘Mary Stoker’ is an early season mum with apricot yellow, single-flower heads.'Tripoli’ blooms very late in the season and has daisy-like flowers of vibrant pink with yellow centers.Start seed indoors, six to eight weeks before your last frost date, and harden off plants before transplanting outdoors.Start seed indoors, six to eight weeks before your last frost date, and harden off plants before transplanting outdoors.Although this method does have extra steps, you have to cut a stem that is at least 4 inches, dip the cut end into a rooting hormone, plant it in a container, wait about four weeks or so for a root to grow and for the plant to grow another 2 inches, then transplant it outside.Unfortunately, the mums for sale in garden centers in the fall have been coddled in nurseries and coaxed to set buds for September blooms.This is not a problem in warmer climates, where a bit of deadheading will satisfy most mums after bloom, but in areas with sub-zero winters, perennial plants need strong roots to anchor them into the ground.The repeated freezing and thawing of the soil will heave the plant out of the ground and kill the roots.Some signs include leaf and stem damage, webbing on the plants, and visible insects.Common diseases include botrytis, leaf spots, rust, powdery mildew, stem and root rots, verticillium wilt, aster yellows, and viruses.Leaf spots and powdery mildew are rarely fatal, but plants with other diseases should be removed and destroyed.
Edward R. Forte
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